Transmitting optical sub-assemblies (TOSAs) used for LAN, wavelength division multiplexing (WDM), or dense wavelength division multiplexing (DWDM) high speed data communication with greater than 40 gigabyte (Gb) transmission rates typically include a continuous light source in the form of one or more semiconductor lasers aligned to an optical modulator section where light is coupled from the laser to the modulator input with the help of individual lenses or lens arrays (to minimize alignment effort). Typically, the lens(es) and modulator are hermetically sealed inside a suitable enclosure to cool the components without forming condensation and to control or tune the wavelength of the laser.
Small form factor transceivers that include TOSAs, like Quad Small Form-factor Pluggable (QSFP or QSFP+), QSFP28, and Small Form-factor Pluggable (SPF), are compact and low cost solutions for optical data transmission. Transmission rates of 40 Gb and 100 Gb often require two PCBs to accommodate all the required components which leaves little space for the transmit and receive portions of the transceivers.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.